The 75th-birthday celebrations of Bernard Haitink have been a lengthy affair, and they still have one party to go.

The 75th-birthday celebrations of Bernard Haitink have been a lengthy affair, and they still have one party to go. Not only have they featured the orchestras that, over Haitink's career, have consistently been Europe's best; they have brought them to the Barbican, where, before the recent acoustic changes, many visiting bands feared to tread. Now it's Haitink who has got even the Berlin Philharmonic there, rather than the orchestra's chief, Simon Rattle, marking a climax not only to the birthday bashes but, in a sense, to the whole trajectory of the great man's music-making.

There was just one piece: the vast Third Symphony of Mahler, one of the composers, alongside Bruckner and Shostakovich, whose ascent into public favour has paralleled the conductor's career and, to an extent, been driven by it. He has often conducted it with London orchestras, but in other halls. Would it fit? The players packed on, within two metres of the front row, but the question was about sound rather than size. Larger symphonies have been crammed into the Barbican, but not played by an orchestra that has been famous for its big sound since the times of Von Karajan.

An explosive bass drum near the start seemed to surprise even the players. But Haitink is not the man for straining tone and hyped-up drama, and while the horns certainly filled the house, they did so with restraint. The full force of the orchestra was kept for three or four peak moments, the impact all the more shattering for leaving the ears space to recover.

In the Barbican's close-up you could enjoy to the full the subtleties of craft and practice that go into making the big picture a great one. Prime among them was the shading of one orchestral colour into another, trumpets into trombones and over to the basses, as one of Mahler's shrill outbursts winds down into a fading growl. The moments when an off-stage posthorn emerges are always magical, but never more seamlessly brought off.

Anna Larsson's warm, secure singing, at a testingly slow pace, was punctuated by a stark note-bending oboe, and into the short choral episode with neat singing from London Symphony Chorus and St Paul's choristers - not enough of them, the one point when size did matter.

At the end, the audience let the final massive chord hang on into a silence as unexpected as it was affecting. Whenever did you hear a British audience do that? It was a greeting more profound than all the subsequent ovations, a tribute not just to a concert but to a life.